The subject matter disclosed herein relates to an optical monitoring system for a gas turbine engine.
Certain gas turbine engines include a turbine and/or a combustor having viewports configured to facilitate monitoring of various components within the turbine and/or the combustor. For example, a pyrometry system may receive radiation signals through the viewports to measure a temperature of certain components within a hot gas path of the gas turbine engine. The pyrometry system may include multiple sensors, each optically coupled to a corresponding viewport and configured to measure the intensity of radiation emitted by the turbine components and/or the combustor components. For example, certain sensors (e.g., optical sensors) are configured to provide a line-of-sight point temperature measurement or an average temperature measurement of each monitored component.
Utilizing an infrared camera having a two-dimensional detector array may provide additional information regarding the performance of each monitored component, such as thermal stress within the component. However, it may be undesirable to position an infrared camera proximate to a viewport due to the heat and vibration generated by the gas turbine engine. For example, if the infrared camera is positioned proximate to the viewport, a cooling system may be employed to maintain the temperature of the infrared camera within a desirable range. Unfortunately, utilizing a cooling system may substantially increase the cost and complexity associated within monitoring the gas turbine engine. Furthermore, employing a fiber optic cable to convey an image from the viewport to a remote infrared camera may be undesirable due to substantial losses associated with typical fiber optic cables. For example, the fiber optic cable may be formed from a material that absorbs radiation within a detectable wavelength range of the infrared camera. Accordingly, electromagnetic radiation emitted by components within the turbine and/or within the combustor may not reach the detector array with sufficient intensity and negligible interference to be detected.